Simplify the following expression: $r = \dfrac{-7p + 9}{5p + 7} \times 7$
Solution: When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{(-7p + 9) \times 7} {(5p + 7) \times 1}$ $r = \dfrac{-49p + 63}{5p + 7}$